This invention relates generally to reaction chamber check valves, and more particularly to a check valve for use adjacent a precombustion chamber of a gaseous fuel internal combustion engine.
Internal combustion engines which burn gaseous fuels containing high amounts of methane, including natural gas or gas produced from a landfill, have a tendency to produce high exhaust emissions. One solution to reducing exhaust emissions from these engines is to burn leaner gaseous fuel/air mixtures. Some engines which use these leaner mixtures include a precombustion chamber that is in fluid communication with the main combustion chamber. A rich mixture is ignited in the precombustion chamber which serves as the means for igniting the leaner mixture in the main combustion chamber. While this engine configuration has been successful in reducing exhaust emissions, other problems have been observed. Engineers have found that solid deposits produced from the gaseous fuel during the combustion process tend to accumulate on the valve that separates the precombustion chamber from the fuel supply passage, which can cause the engine to misfire.
For instance, engines using a precombustion chamber typically use a ball check valve to separate the fuel supply passage from the precombustion chamber. The ball valve in these engines is mechanically unbiased and is moved by pressure differentials existing between the fuel supply passage and the precombustion chamber. In general, the pressure in the fuel supply passage is constant while the pressure in the precombustion chamber fluctuates with the engine cycle. These ball valves are not always able to seal adequately due to the deposit of solids on the valve seat, pressure wave dynamics, and other reasons not fully understood. When the ball valve fails to seal sufficiently, combustion gasses can flow into the fuel supply passage and cause the engine to misfire.
The present invention is directed to overcoming one or more of the problems described above and to improving performance of gaseous fuel internal combustion engines.
An internal combustion engine comprises an engine housing which defines a main combustion chamber that is separated from a precombustion chamber by a flame communication passageway. The engine housing further defines a fuel supply passage with one end and an opposite end. A source of fuel is fluidly connected to the opposite end of the fuel supply passage. A check valve, which includes a valve body with a valve seat and a valve member, is positioned between the one end of the fuel supply passage and the precombustion chamber. The valve member is movable between an open position and a closed position. The valve body and the valve member define a relatively wide fluid passage that fluidly connects the fuel supply passage to the precombustion chamber when the valve member is in the open position. The valve body and the valve member define a relatively narrow stagnation region separating the valve seat from the precombustion chamber when the valve member is in the closed position.